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Vasconcelos A, King JD, Nunes-Alves C, Anderson R, Argaw D, Basáñez MG, Bilal S, Blok DJ, Blumberg S, Borlase A, Brady OJ, Browning R, Chitnis N, Coffeng LE, Crowley EH, Cucunubá ZM, Cummings DAT, Davis CN, Davis EL, Dixon M, Dobson A, Dyson L, French M, Fronterre C, Giorgi E, Huang CI, Jain S, James A, Kim SH, Kura K, Lucianez A, Marks M, Mbabazi PS, Medley GF, Michael E, Montresor A, Mutono N, Mwangi TS, Rock KS, Saboyá-Díaz MI, Sasanami M, Schwehm M, Spencer SEF, Srivathsan A, Stawski RS, Stolk WA, Sutherland SA, Tchuenté LAT, de Vlas SJ, Walker M, Brooker SJ, Hollingsworth TD, Solomon AW, Fall IS. Accelerating Progress Towards the 2030 Neglected Tropical Diseases Targets: How Can Quantitative Modeling Support Programmatic Decisions? Clin Infect Dis 2024; 78:S83-S92. [PMID: 38662692 PMCID: PMC11045030 DOI: 10.1093/cid/ciae082] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024] Open
Abstract
Over the past decade, considerable progress has been made in the control, elimination, and eradication of neglected tropical diseases (NTDs). Despite these advances, most NTD programs have recently experienced important setbacks; for example, NTD interventions were some of the most frequently and severely impacted by service disruptions due to the coronavirus disease 2019 (COVID-19) pandemic. Mathematical modeling can help inform selection of interventions to meet the targets set out in the NTD road map 2021-2030, and such studies should prioritize questions that are relevant for decision-makers, especially those designing, implementing, and evaluating national and subnational programs. In September 2022, the World Health Organization hosted a stakeholder meeting to identify such priority modeling questions across a range of NTDs and to consider how modeling could inform local decision making. Here, we summarize the outputs of the meeting, highlight common themes in the questions being asked, and discuss how quantitative modeling can support programmatic decisions that may accelerate progress towards the 2030 targets.
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Affiliation(s)
- Andreia Vasconcelos
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Old Road Campus, Oxford, United Kingdom
- Centre for Global Health Research, Nuffield Department of Medicine, University of Oxford, Old Road Campus, Oxford, United Kingdom
| | - Jonathan D King
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Cláudio Nunes-Alves
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Old Road Campus, Oxford, United Kingdom
| | - Roy Anderson
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Daniel Argaw
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Shakir Bilal
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - David J Blok
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Seth Blumberg
- Francis I. Proctor Foundation, University of California, San Francisco, California, USA
| | - Anna Borlase
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - Oliver J Brady
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Raiha Browning
- The Department of Statistics, The University of Warwick, Coventry, United Kingdom
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Emily H Crowley
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Zulma M Cucunubá
- Departamento de Epidemiología Clínica y Bioestadística, Facultad de Medicina, Universidad Pontificia Javeriana, Bogotá, Colombia
| | - Derek A T Cummings
- Department of Biology, University of Florida, Gainesville, Florida, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| | - Christopher Neil Davis
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Emma Louise Davis
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Matthew Dixon
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Andrew Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Louise Dyson
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Michael French
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, St Mary's Campus, Imperial College London, London, United Kingdom
- RTI International, Washington, D.C., USA
| | - Claudio Fronterre
- CHICAS, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Emanuele Giorgi
- CHICAS, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Ching-I Huang
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Saurabh Jain
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Ananthu James
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sung Hye Kim
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Klodeta Kura
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Ana Lucianez
- Communicable Diseases Prevention, Control, and Elimination, Pan American Health Organization, Washington D.C., USA
| | - Michael Marks
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Pamela Sabina Mbabazi
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Graham F Medley
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Edwin Michael
- College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Antonio Montresor
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Nyamai Mutono
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
| | - Thumbi S Mwangi
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Nairobi, Kenya
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Kat S Rock
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Martha-Idalí Saboyá-Díaz
- Communicable Diseases Prevention, Control, and Elimination, Pan American Health Organization, Washington D.C., USA
| | - Misaki Sasanami
- Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Markus Schwehm
- ExploSYS GmbH, Interdisciplinary Institute for Exploratory Systems, Leinfelden-Echterdingen, Germany
| | - Simon E F Spencer
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ariktha Srivathsan
- Francis I. Proctor Foundation, University of California, San Francisco, California, USA
| | - Robert S Stawski
- Institute of Public Health and Wellbeing, School of Health and Social Care, University of Essex, Essex, United Kingdom
| | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Samuel A Sutherland
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Warwick Medical School, The University of Warwick, Coventry, United Kingdom
| | | | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, London, United Kingdom
| | | | - T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Old Road Campus, Oxford, United Kingdom
| | - Anthony W Solomon
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Ibrahima Socé Fall
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
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Taylor M, Thomas R, Oliver S, Garner P. Community views on mass drug administration for filariasis: a qualitative evidence synthesis. Cochrane Database Syst Rev 2022; 2:CD013638. [PMID: 35174482 PMCID: PMC8851040 DOI: 10.1002/14651858.cd013638.pub2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The World Health Organization (WHO) recommends mass drug administration (MDA), giving a drug at regular intervals to a whole population, as part of the strategy for several disease control programmes in low- and middle-income countries. MDA is currently WHO policy for areas endemic with lymphatic filariasis, which is a parasitic disease that can result in swollen limbs and disability. The success depends on communities adhering to the drugs given, and this will be influenced by the perception of the drug, the programme, and those delivering it. OBJECTIVES: To synthesize qualitative research evidence about community experience with, and understanding and perception of, MDA programmes for lymphatic filariasis. To explore whether programme design and delivery influence the community experience identified in the analysis. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, and seven other databases up to 8 April 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies. SELECTION CRITERIA This review synthesized qualitative research and mixed-methods studies when it was possible to extract qualitative data. Eligible studies explored community experiences, perceptions, or attitudes towards MDA programmes for lymphatic filariasis in any country, conducted between 2000 and 2019. DATA COLLECTION AND ANALYSIS: We extracted data on study design including: authors, aims, participants, methods, and qualitative data collection methods. We also described programme delivery factors including: country, urban or rural setting, endemicity, drug regimen, rounds of MDA received at the time of the study, who delivered the drugs, how the drugs were delivered, use of health education, and sensitization and adherence monitoring. We conducted a thematic analysis and developed codes inductively using ATLAS.ti software. We examined codes for underlying ideas, connections, and interpretations and, from this, generated analytical themes. We assessed the confidence in the findings using the GRADE-CERQual approach, and produced a conceptual model to display our findings. MAIN RESULTS: From 902 results identified in the search, 29 studies met our inclusion criteria. The studies covered a broad range of countries in Africa, South-East Asia, and South America, and explored the views and experiences of community members and community drug distributors in low-income countries endemic for lymphatic filariasis. Four themes emerged. People weigh up benefits and harms before participating. People understand the potential benefits in terms of relief of suffering, stigma, and avoiding costs (high confidence); however, these theoretical benefits do not always mesh with their experiences (high confidence). In particular, adverse effects are frightening and unwelcome (high confidence); and these effects are amplified through rumour and social media (moderate confidence). Many people are suspicious of MDA programmes. When people lack a scientific explanation for the programme and their experiences of it, they often develop social explanations instead. These are largely shaped on the historical backdrop and level of trust people have in relevant authority figures (high confidence), although some have unwavering faith in their government and, by extension, the programme (moderate confidence). Programmes expect compliance, and this can become coercive and blaming. Health workers and community members stigmatize non-compliance, which can become coercive (moderate confidence), so communities may appear to comply publicly, but privately reject treatment (moderate confidence). Community distributors are often not respected or valued. They have little authority (moderate confidence), and the behaviour of some distributors damages the MDA programme's reputation (high confidence). Communities want information about programmes to help make decisions about participation, but drug distributors are not sufficiently informed, or skilled in this communication (high confidence). We intended to assess whether programme designs influenced communities' perceptions of the programme and decision to adhere but were unable to do so as few studies adequately reported the design and implementation of the local programme. We have moderate to high confidence in the evidence contributing to the review themes and subthemes. AUTHORS' CONCLUSIONS Adherence with MDA for filariasis is influenced by individual direct experience of benefit and harm; social influences in the community; political influences and their relationship to government; and historical influences. Fear of adverse effects was frequently described and this appears to be particularly important for communities. When views were negative, we were surprised by the strength of feeling expressed. Enthusiasm for these schemes as a strategy in global policy needs debate in the light of these findings.
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Affiliation(s)
- Melissa Taylor
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Rebecca Thomas
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Sandy Oliver
- EPPI-Centre, Social Science Research Unit, UCL Institute of Education, University College London, London, UK
- Africa Centre for Evidence, Faculty of Humanities, University of Johannesburg, Johannesburg, South Africa
| | - Paul Garner
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Division of Epidemiology and Biostatistics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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Sabesan S, Krishnamoorthy K, Hoti S, Subramanian S, Srividya A, Roy N, Jain T, Kumar A, Rahi M. Diethylcarbamazine citrate-fortified salt for lymphatic filariasis elimination in India. Indian J Med Res 2022; 155:347-355. [PMID: 36124509 PMCID: PMC9707683 DOI: 10.4103/ijmr.ijmr_171_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lymphatic filariasis (LF) is a vector-borne neglected tropical disease, causing permanent disability. The disease is debilitating and widespread, leading to tremendous productivity and economic loss. The Government of India (GOI) prioritized the elimination of LF through the annual mass drug administration (MDA) programme in 2004 and continued with a single dose of diethylcarbamazine citrate (DEC), 6 mg/kg of body weight, plus albendazole annually over a period of 5-6 years. The GOI had set the target to achieve LF elimination by 2015 and now by 2030. The progress so far has been suboptimal. Much remains to be done as about 84 per cent of the total 328 endemic districts are still under MDA. The major challenge in implementing MDA is poor compliance. It is necessary to have a feasible alternative strategy addressing the above challenge to achieve the desired goal of LF elimination. At this juncture, a well-researched approach, i.e. the use of DEC-fortified salt, also advocated by the World Health Organization, as a unique form of MDA, is proposed. As per this strategy, a low dose of DEC (0.2% w/w) is added to the cooking salt at the manufacturing facility of iodized salt and consumed by the LF-endemic communities for about two years. Many examples of successful use of this strategy for LF elimination in small- and large-scale trials have been documented in India and several other endemic countries in the world. Implementing DEC-iodine-fortified salt is a safe, less expensive, more efficient and prompt approach for achieving the elimination of LF in India. Adverse effects are none or minor and self-limiting. The DEC-fortified salt strategy can easily piggyback on the existing countrywide deployment of iodized salt under the National Iodine Deficiency Disorders Control Programme (NIDDCP), which has achieved a great success in reducing iodine-deficiency disorders such as hypothyroidism. This existing robust programme can be leveraged to launch DEC-fortified salt for the community. If implemented appropriately, this strategy will ensure the complete cessation of LF transmission within two years from its introduction. If the said strategy is implemented in 2022, it is expected that India will be able to achieve the LF elimination by 2024, much before the global target of 2030.
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Affiliation(s)
- S. Sabesan
- Vector Control Research Centre, Puducherry, India
| | | | - S.L. Hoti
- Vector Control Research Centre, Puducherry, India
| | | | - A. Srividya
- Vector Control Research Centre, Puducherry, India
| | - Nupur Roy
- National Centre for Vector-Borne Disease Control, Directorate General of Health Services, Ministry of Health and Family Welfare, Government of India, India
| | - Tanu Jain
- National Centre for Vector-Borne Disease Control, Directorate General of Health Services, Ministry of Health and Family Welfare, Government of India, India
| | | | - Manju Rahi
- Division of Epidemiology & Communicable Diseases, Indian Council of Medical Research, New Delhi, India,For correspondence: Dr Manju Rahi, Division of Epidemiology & Communicable Diseases, Indian Council of Medical Research, New Delhi 110 029, India e-mail:
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Taylor M, Oliver S, Garner P. Mass drug administration for filariasis: community views and programme design influences - a qualitative evidence synthesis. Hippokratia 2020. [DOI: 10.1002/14651858.cd013638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Melissa Taylor
- Department of Clinical Sciences; Liverpool School of Tropical Medicine; Liverpool UK
| | - Sandy Oliver
- EPPI-Centre, Social Science Research Unit, UCL Institute of Education; University College London; London UK
| | - Paul Garner
- Department of Clinical Sciences; Liverpool School of Tropical Medicine; Liverpool UK
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Drug Repurposing of Bromodomain Inhibitors as Potential Novel Therapeutic Leads for Lymphatic Filariasis Guided by Multispecies Transcriptomics. mSystems 2019; 4:4/6/e00596-19. [PMID: 31796568 PMCID: PMC6890932 DOI: 10.1128/msystems.00596-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The current treatment regimen for lymphatic filariasis is mostly microfilaricidal. In an effort to identify new drug candidates for lymphatic filariasis, we conducted a three-way transcriptomics/systems biology study of one of the causative agents of lymphatic filariasis, Brugia malayi, its Wolbachia endosymbiont wBm, and its vector host Aedes aegypti at 16 distinct B. malayi life stages. B. malayi upregulates the expression of bromodomain-containing proteins in the adult female, embryo, and microfilaria stages. In vitro, we find that the existing cancer therapeutic JQ1(+), which is a bromodomain and extraterminal protein inhibitor, has adulticidal activity in B. malayi. To better understand the transcriptomic interplay of organisms associated with lymphatic filariasis, we conducted multispecies transcriptome sequencing (RNA-Seq) on the filarial nematode Brugia malayi, its Wolbachia endosymbiont wBm, and its laboratory vector Aedes aegypti across the entire B. malayi life cycle. In wBm, transcription of the noncoding 6S RNA suggests that it may be a regulator of bacterial cell growth, as its transcript levels correlate with bacterial replication rates. For A. aegypti, the transcriptional response reflects the stress that B. malayi infection exerts on the mosquito with indicators of increased energy demand. In B. malayi, expression modules associated with adult female samples consistently contained an overrepresentation of genes involved in chromatin remodeling, such as the bromodomain-containing proteins. All bromodomain-containing proteins encoded by B. malayi were observed to be upregulated in the adult female, embryo, and microfilaria life stages, including 2 members of the bromodomain and extraterminal (BET) protein family. The BET inhibitor JQ1(+), originally developed as a cancer therapeutic, caused lethality of adult worms in vitro, suggesting that it may be a potential therapeutic that can be repurposed for treating lymphatic filariasis. IMPORTANCE The current treatment regimen for lymphatic filariasis is mostly microfilaricidal. In an effort to identify new drug candidates for lymphatic filariasis, we conducted a three-way transcriptomics/systems biology study of one of the causative agents of lymphatic filariasis, Brugia malayi, its Wolbachia endosymbiont wBm, and its vector host Aedes aegypti at 16 distinct B. malayi life stages. B. malayi upregulates the expression of bromodomain-containing proteins in the adult female, embryo, and microfilaria stages. In vitro, we find that the existing cancer therapeutic JQ1(+), which is a bromodomain and extraterminal protein inhibitor, has adulticidal activity in B. malayi.
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Smith ME, Singh BK, Michael E. Assessing endgame strategies for the elimination of lymphatic filariasis: A model-based evaluation of the impact of DEC-medicated salt. Sci Rep 2017; 7:7386. [PMID: 28785097 PMCID: PMC5547057 DOI: 10.1038/s41598-017-07782-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 07/04/2017] [Indexed: 12/27/2022] Open
Abstract
Concern is growing regarding the prospects of achieving the global elimination of lymphatic filariasis (LF) by 2020. Apart from operational difficulties, evidence is emerging which points to unique challenges that could confound achieving LF elimination as extinction targets draw near. Diethylcarbamazine (DEC)-medicated salt may overcome these complex challenges posed by the endgame phase of parasite elimination. We calibrated LF transmission models using Bayesian data-model assimilation techniques to baseline and follow-up infection data from 11 communities that underwent DEC salt medication. The fitted models were used to assess the utility of DEC salt treatment for achieving LF elimination, in comparison with other current and proposed drug regimens, during the endgame phase. DEC-medicated salt consistently reduced microfilaria (mf) prevalence from 1% mf to site-specific elimination thresholds more quickly than the other investigated treatments. The application of DEC salt generally required less than one year to achieve site-specific LF elimination, while annual and biannual MDA options required significantly longer durations to achieve the same task. The use of DEC-medicated salt also lowered between-site variance in extinction timelines, especially when combined with vector control. These results indicate that the implementation of DEC-medicated salt, where feasible, can overcome endgame challenges facing LF elimination programs.
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Affiliation(s)
- Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Brajendra K Singh
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
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Narahari SR, Aggithaya MG, Moffatt C, Ryan TJ, Keeley V, Vijaya B, Rajendran P, Karalam SB, Rajagopala S, Kumar NK, Bose KS, Sushma KV. Future Research Priorities for Morbidity Control of Lymphedema. Indian J Dermatol 2017; 62:33-40. [PMID: 28216723 PMCID: PMC5286751 DOI: 10.4103/0019-5154.198039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Background: Innovation in the treatment of lower extremity lymphedema has received low priority from the governments and pharmaceutical industry. Advancing lymphedema is irreversible and initiates fibrosis in the dermis, reactive changes in the epidermis and subcutis. Most medical treatments offered for lymphedema are either too demanding with a less than satisfactory response or patients have low concordance due to complex schedules. A priority setting partnership (PSP) was established to decide on the future priorities in lymphedema research. Methods: A table of abstracts following a literature search was published in workshop website. Stake holders were requested to upload their priorities. Their questions were listed, randomized, and sent to lymphologists for ranking. High ranked ten research priorities, obtained through median score, were presented in final prioritization work shop attended by invited stake holders. A free medical camp was organized during workshop to understand patients’ priorities. Results: One hundred research priorities were selected from priorities uploaded to website. Ten priorities were short listed through a peer review process involving 12 lymphologists, for final discussion. They were related to simplification of integrative treatment for lymphedema, cellular changes in lymphedema and mechanisms of its reversal, eliminating bacterial entry lesions to reduce cellulitis episodes, exploring evidence for therapies in traditional medicine, improving patient concordance to compression therapy, epidemiology of lymphatic filariasis (LF), and economic benefit of integrative treatments of lymphedema. Conclusion: A robust research priority setting process, organized as described in James Lind Alliance guidebook, identified seven priority areas to achieve effective morbidity control of lymphedema including LF. All stake holders including Department of Health Research, Government of India, participated in the PSP.
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Affiliation(s)
- S R Narahari
- Institute of Applied Dermatology, Central University of Kerala, Kasaragod, Kerala, India
| | | | - Christine Moffatt
- International Lymphoedema Framework, London; Division of Nursing and Healthcare, Faculty of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - T J Ryan
- Department of Dermatology, Churchill Hospital, Oxford, United Kingdom
| | - Vaughan Keeley
- Department of Lymphedema, Royal Derby Hospital, Derby, United Kingdom
| | - B Vijaya
- Department of Pathology, JSS Medical College, JSS University, Mysore, Karnataka, India
| | - P Rajendran
- Department of Biochemistry and Molecular Biology, Central University of Kerala, Kasaragod, Kerala, India
| | - S B Karalam
- Department of R&D, Oushadhi Ltd, Thrissur, Kerala, India
| | - S Rajagopala
- Department of Kaumarabhritya, Institute for Postgraduate Teaching and Research in Ayurveda, Jamnagar, Gujarat, India
| | - N K Kumar
- Dr. TMA Pai Endowment Chair, Manipal University, Indian Council for Medical Research, Chennai, Tamil Nadu, India
| | - K S Bose
- Institute of Applied Dermatology, Central University of Kerala, Kasaragod, Kerala, India
| | - K V Sushma
- Institute of Applied Dermatology, Central University of Kerala, Kasaragod, Kerala, India
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Mhashilkar AS, Vankayala SL, Liu C, Kearns F, Mehrotra P, Tzertzinis G, Palli SR, Woodcock HL, Unnasch TR. Identification of Ecdysone Hormone Receptor Agonists as a Therapeutic Approach for Treating Filarial Infections. PLoS Negl Trop Dis 2016; 10:e0004772. [PMID: 27300294 PMCID: PMC4907521 DOI: 10.1371/journal.pntd.0004772] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/21/2016] [Indexed: 11/27/2022] Open
Abstract
Background A homologue of the ecdysone receptor has previously been identified in human filarial parasites. As the ecdysone receptor is not found in vertebrates, it and the regulatory pathways it controls represent attractive potential chemotherapeutic targets. Methodology/ Principal Findings Administration of 20-hydroxyecdysone to gerbils infected with B. malayi infective larvae disrupted their development to adult stage parasites. A stable mammalian cell line was created incorporating the B. malayi ecdysone receptor ligand-binding domain, its heterodimer partner and a secreted luciferase reporter in HEK293 cells. This was employed to screen a series of ecdysone agonist, identifying seven agonists active at sub-micromolar concentrations. A B. malayi ecdysone receptor ligand-binding domain was developed and used to study the ligand-receptor interactions of these agonists. An excellent correlation between the virtual screening results and the screening assay was observed. Based on both of these approaches, steroidal ecdysone agonists and the diacylhydrazine family of compounds were identified as a fruitful source of potential receptor agonists. In further confirmation of the modeling and screening results, Ponasterone A and Muristerone A, two compounds predicted to be strong ecdysone agonists stimulated expulsion of microfilaria and immature stages from adult parasites. Conclusions The studies validate the potential of the B. malayi ecdysone receptor as a drug target and provide a means to rapidly evaluate compounds for development of a new class of drugs against the human filarial parasites. The human filarial parasites are the causative agents of two neglected tropical diseases targeted for elimination by the international community. The current elimination programs rely upon the mass distribution of a limited number of drugs, leaving the programs open to failure in the event that resistance develops. Thus, there is a critical need for novel chemotherapeutic agents to supplement the current arsenal. The filarial parasites are ecdysozoans, whose developmental processes are controlled by a master regulator, the ecdysone receptor. Here we validate the potential of the filarial ecdysone receptor as a chemotherapeutic target and report the development of high throughput and virtual screening assays that may be used to compounds that target it.
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Affiliation(s)
- Amruta S. Mhashilkar
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Sai L. Vankayala
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Canhui Liu
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Fiona Kearns
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Priyanka Mehrotra
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - George Tzertzinis
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Subba R. Palli
- Department of Entomology, University of Kentucky, Lexington, Kentucky, United States of America
| | - H. Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Thomas R. Unnasch
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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9
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Shriram A, Krishnamoorthy K, Vijayachari P. Diurnally subperiodic filariasis among the Nicobarese of Nicobar district - epidemiology, vector dynamics & prospects of elimination. Indian J Med Res 2015; 141:598-607. [PMID: 26139777 PMCID: PMC4510758 DOI: 10.4103/0971-5916.159537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Indexed: 12/03/2022] Open
Abstract
In India diurnally subperiodic filariasis (DspWB) is prevalent only in the Nicobar district of Andaman and Nicobar Islands. Studies undertaken at different points of time indicate that this form of filariasis is restricted to a small region in Nancowry group of islands where it is transmitted by mosquito Downsiomyia nivea, a day biting mosquito. Studies on prevalence, distribution, and assessment of endemicity status, vector incrimination, bioecology, host seeking behaviour, population dynamics of the vector, transmission dynamics and clinical epidemiology indicate the prevalence and persistence of this infection in the Nancowry group of islands with perennial transmission. There was no control programme in these islands, until the National programme to eliminate filariasis was launched in 2004. Eight rounds of annual mass drug administration (MDA) with diethyl carbamazine (DEC) + albendazole have been completed. Despite this, microfilaria prevalence remains at above one per cent, the level identified for initiating transmission assessment survey to decide on continuation of MDA further. This necessitates adjunct measures to the ongoing MDA programme in these islands. The vector control options could be an adjunct measure, but the vector is a forest dweller with a unique bio-ecology, therefore, not a technically feasible option. Use of DEC fortified salt for six months to one year could hasten the process of elimination. Although administration of DEC-fortified salt is simple, rapid, safe, and cost-effective, challenges are to be tackled for evolving operationally realistic strategy. Such a strategy requires commitment of all sections of the society, a distribution mechanism that ensures the use of DEC-fortified salt in the Nancowry islands. Here we discuss the plan of action to serve the indigenous communities and operationalizing DEC fortified salt strategy through an inter-sectoral approach involving multiple stakeholders.
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Affiliation(s)
- A.N. Shriram
- Vector Control Research Centre (ICMR) Puducherry, India
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10
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Metzger WG, Mordmüller B. Loa loa—does it deserve to be neglected? THE LANCET. INFECTIOUS DISEASES 2014; 14:353-7. [DOI: 10.1016/s1473-3099(13)70263-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Jawaharlal JPP, Ravishankaran R, Shridharan RN, Lawrence AV, Karande AA, Perumal K. Evaluation of Brugia malayi sheath protein (Shp-1) as a diagnostic antigen for human lymphatic filariasis. Diagn Microbiol Infect Dis 2014; 78:249-54. [PMID: 24389369 DOI: 10.1016/j.diagmicrobio.2013.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 11/14/2013] [Accepted: 11/16/2013] [Indexed: 11/19/2022]
Abstract
Lymphatic filariasis is the second leading cause of permanent long-term disability globally and control of this disease needs efficient diagnostic methods. In this study, abundantly expressing microfilarial sheath protein (Shp-1) from Brugia malayi was characterized as a filarial diagnostic candidate using samples from different clinical population. Monoclonal antibodies were developed against E. coli expressed recombinant Shp-1 in order to assess its efficiency in filarial antigen detection assay system. Endemic Normal (EN, n = 170), asymptomatic microfilaeremics (MF, n = 65), symptomatic chronic pathology (CP, n = 45) and non endemic normal (NEN, n = 10) sera were analyzed by antigen capture enzyme-linked immunosorbent assay. Of the 290 individuals, all MF individuals (both brugian and bancroftian) were positive in this assay followed by CP and EN. When compared with SXP-1 and Og4C3 antigen assays, all assays detected Wb MF correctly, Bm MF was detected by Shp-1 and SXP-1 assays, and only Shp-1 was able to detect EN (12%) and CP (29%). Results showed that this assay may be useful for monitoring prior to mass drug administration.
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Affiliation(s)
| | | | | | | | - Anjali Anoop Karande
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.
| | - Kaliraj Perumal
- Centre for Biotechnology, Anna University, Chennai, Tamil Nadu, India.
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12
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McAlister VC, Trottier V. Role of persistent processus vaginalis in hydroceles found in a tropical population. Can J Surg 2013; 56:E29-31. [PMID: 23706855 DOI: 10.1503/cjs.000112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Lymphatic obstruction by Wuchereria bancrofti is thought to be the mechanism for development of tropical hydrocele in men and for elephantiasis, mostly in women. Hydrocele prevalence is used to determine the effectiveness of para site eradication programs. METHODS We maintained a prospective log of operations performed at 1 Canadian Field Hospital during its relief mission to Léogâne, Haiti. Information regarding duration of symptoms, type of previous surgery (if any), surgical approach, associated inguinal hernia and volume and appearance of hydrocele fluid in patients with tropical hydroceles were recorded. RESULTS From January to March 2010, 4922 patients were seen, none of whom had elephantiasis. Of the 64 patients who collectively underwent 69 inguino-scrotal procedures, 5 patients had inguinal hernia repair several years after hydrocele excision via the scrotum, 19 patients with bilateral hydroceles underwent a scrotum-only approach, and 45 patients had an inguinal approach (33 unilateral and 12 bilateral) to repair 57 hydroceles. A patent processus vaginalis was present in 50 of 57 (88%) hydroceles where the groin was explored. CONCLUSION Hydroceles remain common in Léogâne despite successful eradication of filariasis with mass drug administration using diethylcarbamazine-fortified cooking salt. Persistent patent processus vaginalis is a more likely cause than persistent filariasis. There is probably little difference between hydrocele in developed countries and tropical hydrocele other than neglect. Hydrocele prevalence is not a measure of the effectiveness of parasite eradication programs.
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13
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Orrskog S, Medin E, Tsolova S, Semenza JC. Causal inference regarding infectious aetiology of chronic conditions: a systematic review. PLoS One 2013; 8:e68861. [PMID: 23935899 PMCID: PMC3723854 DOI: 10.1371/journal.pone.0068861] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 05/31/2013] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The global burden of disease has shifted from communicable diseases in children to chronic diseases in adults. This epidemiologic shift varies greatly by region, but in Europe, chronic conditions account for 86% of all deaths, 77% of the disease burden, and up to 80% of health care expenditures. A number of risk factors have been implicated in chronic diseases, such as exposure to infectious agents. A number of associations have been well established while others remain uncertain. METHODS AND FINDINGS We assessed the body of evidence regarding the infectious aetiology of chronic diseases in the peer-reviewed literature over the last decade. Causality was assessed with three different criteria: First, the total number of associations documented in the literature between each infectious agent and chronic condition; second, the epidemiologic study design (quality of the study); third, evidence for the number of Hill's criteria and Koch's postulates that linked the pathogen with the chronic condition. We identified 3136 publications, of which 148 were included in the analysis. There were a total of 75 different infectious agents and 122 chronic conditions. The evidence was strong for five pathogens, based on study type, strength and number of associations; they accounted for 60% of the associations documented in the literature. They were human immunodeficiency virus, hepatitis C virus, Helicobacter pylori, hepatitis B virus, and Chlamydia pneumoniae and were collectively implicated in the aetiology of 37 different chronic conditions. Other pathogens examined were only associated with very few chronic conditions (≤ 3) and when applying the three different criteria of evidence the strength of the causality was weak. CONCLUSIONS Prevention and treatment of these five pathogens lend themselves as effective public health intervention entry points. By concentrating research efforts on these promising areas, the human, economic, and societal burden arising from chronic conditions can be reduced.
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Affiliation(s)
| | - Emma Medin
- Heron Evidence Development AB, Stockholm, Sweden
- Karolinska Institutet, Stockholm, Sweden
| | - Svetla Tsolova
- European Centres for Disease Prevention and Control, Stockholm, Sweden
| | - Jan C. Semenza
- European Centres for Disease Prevention and Control, Stockholm, Sweden
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14
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Affiliation(s)
- Sukrti Nagpal
- Royal Surrey County Hospital, Guildford, Surrey, United Kingdom.
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15
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Weaver A, Brown P, Huey S, Magallon M, Bollman EB, Mares D, Streit TG, Lieberman M. A low-tech analytical method for diethylcarbamazine citrate in medicated salt. PLoS Negl Trop Dis 2011; 5:e1005. [PMID: 21347443 PMCID: PMC3035663 DOI: 10.1371/journal.pntd.0001005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 12/04/2010] [Indexed: 11/18/2022] Open
Abstract
The World Health Organization has called for an effort to eliminate Lymphatic Filariasis (LF) around the world. In regions where the disease is endemic, local production and distribution of medicated salt dosed with diethylcarbamazine (DEC) has been an effective method for eradicating LF. A partner of the Notre Dame Haiti program, Group SPES in Port-au-Prince, Haiti, produces a medicated salt called Bon Sel. Coarse salt is pre-washed and sprayed with a solution of DEC citrate and potassium iodate. Iodine levels are routinely monitored on site by a titrimetric method. However, the factory had no method for monitoring DEC. Critical analytical issues include 1) determining whether the amount of DEC in each lot of Bon Sel is within safe and therapeutically useful limits, 2) monitoring variability within and between production runs, and 3) determining the effect of a common local practice (washing salt before use) on the availability of DEC. This paper describes a novel titrimetric method for analysis of DEC citrate in medicated salt. The analysis needs no electrical power and requires only a balance, volumetric glassware, and burets that most salt production programs have on hand for monitoring iodine levels. The staff of the factory used this analysis method on site to detect underloading of DEC on the salt by their sprayer and to test a process change that fixed the problem. As researchers develop more sophisticated technologies, parts of the world are left behind. The front lines of fighting many diseases lie in regions where expensive technology is not feasible. As part of the effort to eradicate lymphatic filariasis in Haiti, our group's goal was to design an assay that would allow a chemist, with basic equipment, to quantify the levels of diethylcarbamazine citrate on medicated salt. With access to university research facilities, we were able to devise and test a back-titration procedure that can measure the medication levels with sufficient accuracy and precision. Our method capitalized on the fact that the medication is acidic. This characteristic allows us to combine an unknown, medicated salt sample with a known quantity of base and then back-titrate with acid to determine diethylcarbamazine citrate concentration based on the neutralization point. Developing this protocol has put the power of quality control into the hands of the Haitian factory producing the medicated salt. With the ability to better monitor dosing levels, we have increased the effectiveness of this program in Haiti. Using modern research facilities to produce effective, low-tech methods could be a useful approach for tackling many worldwide medical and environmental issues.
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Affiliation(s)
- Abigail Weaver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Patrick Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Shannon Huey
- Brigham Young University, Provo, Utah, United States of America
| | - Marco Magallon
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - E. Brennan Bollman
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
| | | | - Thomas G. Streit
- Department of Biology, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Marya Lieberman
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
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Diurnally subperiodic filariasis in India-prospects of elimination: precept to action? Parasitol Res 2011; 109:1-8. [PMID: 21286754 DOI: 10.1007/s00436-011-2252-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Accepted: 01/12/2011] [Indexed: 10/18/2022]
Abstract
The elimination of lymphatic filariasis in the Andaman and Nicobar Islands provides unique opportunities and challenges at the same time. Since these islands are remote, are sparsely populated, and have poor transport networks, mass drug administration programs are likely to be difficult to implement. Diurnally subperiodic Wuchereria bancrofti vectored by Downsiomyia nivea was considered for the scope of vector control options. Considering the bioecology of this mosquito, vector control including personal protection measures may not be feasible. However, since these islands are covered by separate administrative machinery which also plays an important role in regulating the food supply, the use of diethylcarbamazine (DEC)-fortified salt as a tool for the interruption of transmission is appealing. DEC-fortified salt has been successfully pilot tested in India and elsewhere, operationally used by China for eliminating lymphatic filariasis. Administration of DEC-fortified salt though simple, rapid, safe, and cost-effective, challenges are to be tackled for translating this precept into action by evolving operationally feasible strategy. Although the use of DEC-fortified salt is conceptually simple, it requires commitment of all sections of the society, an elaborate distribution mechanism that ensures the use of DEC-fortified salt only in the endemic communities, and a vigorous monitoring mechanism. Here, we examine the inbuilt administrative mechanisms to serve the tribal people, health infrastructure, and public distribution system and discuss the prospects of putting in place an operationally feasible strategy for its elimination.
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Current evidence on the use of antifilarial agents in the management of bancroftian filariasis. J Trop Med 2010; 2011:175941. [PMID: 21234244 PMCID: PMC3018634 DOI: 10.1155/2011/175941] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Accepted: 11/29/2010] [Indexed: 11/17/2022] Open
Abstract
Many trials have explored the efficacy of individual drugs and drug combinations to treat bancroftian filariasis. This narrative review summarizes the current evidence for drug management of bancroftian filariasis.
Diethylcarbamazine (DEC) remains the prime antifilarial agent with a well-established microfilaricidal and some macrofilaricidal effects. Ivermectin (IVM) is highly microfilaricidal but minimally macrofilaricidal. The role of albendazole (ALB) in treatment regimens is not well established though the drug has a microfilaricidal effect. The combination of DEC+ALB has a better long-term impact than IVM+ALB. Recent trials have shown that doxycycline therapy against Wolbachia, an endosymbiotic bacterium of the parasite, is capable of reducing microfilaria rates and adult worm activity. Followup studies on mass drug administration (MDA) are yet to show a complete interruption of transmission, though the infection rates are reduced to a very low level.
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Abstract
BACKGROUND Primary malaria prevention on a large scale depends on two vector control interventions: indoor residual spraying (IRS) and insecticide-treated mosquito nets (ITNs). Historically, IRS has reduced malaria transmission in many settings in the world, but the health effects of IRS have never been properly quantified. This is important, and will help compare IRS with other vector control interventions. OBJECTIVES To quantify the impact of IRS alone, and to compare the relative impacts of IRS and ITNs, on key malariological parameters. SEARCH STRATEGY We searched the Cochrane Infectious Diseases Group Specialized Register (September 2009), CENTRAL (The Cochrane Library 2009, Issue 3), MEDLINE (1966 to September 2009), EMBASE (1974 to September 2009), LILACS (1982 to September 2009), mRCT (September 2009), reference lists, and conference abstracts. We also contacted researchers in the field, organizations, and manufacturers of insecticides (June 2007). SELECTION CRITERIA Cluster randomized controlled trials (RCTs), controlled before-and-after studies (CBA) and interrupted time series (ITS) of IRS compared to no IRS or ITNs. Studies examining the impact of IRS on special groups not representative of the general population, or using insecticides and dosages not recommended by the World Health Organization (WHO) were excluded. DATA COLLECTION AND ANALYSIS Two authors independently reviewed trials for inclusion. Two authors extracted data, assessed risk of bias and analysed the data. Where possible, we adjusted confidence intervals (CIs) for clustering. Studies were grouped into those comparing IRS with no IRS, and IRS compared with ITNs, and then stratified by malaria endemicity. MAIN RESULTS IRS versus no IRSStable malaria (entomological inoculation rate (EIR) > 1): In one RCT in Tanzania IRS reduced re-infection with malaria parasites detected by active surveillance in children following treatment; protective efficacy (PE) 54%. In the same setting, malaria case incidence assessed by passive surveillance was marginally reduced in children aged one to five years; PE 14%, but not in children older than five years (PE -2%). In the IRS group, malaria prevalence was slightly lower but this was not significant (PE 6%), but mean haemoglobin was higher (mean difference 0.85 g/dL).In one CBA trial in Nigeria, IRS showed protection against malaria prevalence during the wet season (PE 26%; 95% CI 20 to 32%) but not in the dry season (PE 6%; 95% CI -4 to 15%). In one ITS in Mozambique, the prevalence was reduced substantially over a period of 7 years (from 60 to 65% prevalence to 4 to 8% prevalence; the weighted PE before-after was 74% (95% CI 72 to 76%).Unstable malaria (EIR < 1): In two RCTs, IRS reduced the incidence rate of all malaria infections;PE 31% in India, and 88% (95% CI 69 to 96%) in Pakistan. By malaria species, IRS also reduced the incidence of P. falciparum (PE 93%, 95% CI 61 to 98% in Pakistan) and P. vivax (PE 79%, 95% CI 45 to 90% in Pakistan); There were similar impacts on malaria prevalence for any infection: PE 76% in Pakistan; PE 28% in India. When looking separately by parasite species, for P. falciparum there was a PE of 92% in Pakistan and 34% in India; for P. vivax there was a PE of 68% in Pakistan and no impact demonstrated in India (PE of -2%).IRS versus Insecticide Treated Nets (ITNs)Stable malaria (EIR > 1): Only one RCT was done in an area of stable transmission (in Tanzania). When comparing parasitological re-infection by active surveillance after treatment in short-term cohorts, ITNs appeared better, but it was likely not to be significant as the unadjusted CIs approached 1 (risk ratio IRS:ITN = 1.22). When the incidence of malaria episodes was measured by passive case detection, no difference was found in children aged one to five years (risk ratio = 0.88, direction in favour of IRS). No difference was found for malaria prevalence or haemoglobin.Unstable malaria (EIR < 1): Two studies; for incidence and prevalence, the malaria rates were higher in the IRS group compared to the ITN group in one study. Malaria incidence was higher in the IRS arm in India (risk ratio IRS:ITN = 1.48) and in South Africa (risk ratio 1.34 but the cluster unadjusted CIs included 1). For malaria prevalence, ITNs appeared to give better protection against any infection compared to IRS in India (risk ratio IRS:ITN = 1.70) and also for both P. falciparum (risk ratio IRS:ITN = 1.78) and P. vivax (risk ratio IRS:ITN = 1.37). AUTHORS' CONCLUSIONS Historical and programme documentation has clearly established the impact of IRS. However, the number of high-quality trials are too few to quantify the size of effect in different transmission settings. The evidence from randomized comparisons of IRS versus no IRS confirms that IRS reduces malaria incidence in unstable malaria settings, but randomized trial data from stable malaria settings is very limited. Some limited data suggest that ITN give better protection than IRS in unstable areas, but more trials are needed to compare the effects of ITNs with IRS, as well as to quantify their combined effects.
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Affiliation(s)
- Bianca Pluess
- Swiss Tropical and Public Health InstitutePublic Health and EpidemiologyBaselSwitzerland4002
| | - Frank C Tanser
- University of KwaZulu‐NatalAfrica Centre for Health and Population StudiesPO Box 198MtubatubaSouth Africa3935
| | - Christian Lengeler
- Swiss Tropical and Public Health InstitutePublic Health and EpidemiologyBaselSwitzerland4002
| | - Brian L Sharp
- Medical Research CouncilMalaria Research Lead Programme491 Ridge RoadOverportDurbanSouth Africa4067
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Abstract
Filariasis is an infectious disease of the lymphatics and subcutaneous tissues caused by nematodes or filariae. Carried by mosquito vectors, this disease causes millions of people to suffer from lymphedema and elephantiasis, characteristics of filariasis infection. This disease can be diagnosed through the identification of microfilariae in blood or skin samples, antigen detection, radiographic imaging, or polymerase chain reaction. Mass drug administration by the World Health Organization has helped to diminish the incidence of filariasis. However, continued research on new drugs and vaccinations will be needed to control and reduce the microfilarial levels in the human population.
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